What Lithium Batteries Are Needed For A Screwdriver
Conversion of a screwdriver to lithium batteries 18650
Every craftsman is faced with the problem of reduced tool performance, or complete failure due to the battery. Manufacturers use nickel-cadmium batteries in 12-volt, 14-volt, 18-volt screwdrivers. The sequential assembly of several elements creates the desired voltage. Replacing nickel-cadmium batteries with lithium batteries extends battery life by making the design lighter. Mandatory BMS board installation adds reliability. Therefore, the conversion of a screwdriver to lithium batteries, mainly to the 18650 form factor, is justified.
Let’s start with the benefits:
- The energy density of lithium-ion cells is much higher than that of nickel-cadmium, which are used by default in screwdrivers. That is, the battery on lithium cans will have less weight than on cadmium with the same capacity and output voltage;
- Lithium battery cells are charged significantly faster than Ni-Cd. It will take about an hour to charge them safely;
- Lithium Ion batteries have no memory effect. This means that they do not need to be fully discharged before charging.
Now about the disadvantages and complexities of lithium batteries.
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Replacing the batteries in the screwdriver with lithium ones. All pros and cons of converting a screwdriver battery to lithium cells
First you need to think about whether I need this alteration? After all, it will be an outright “self-propeller” and in some cases can lead to failure of both the battery and the screwdriver itself. Therefore, let’s consider all the pros and cons of this procedure. It is possible that after that some of you will decide to abandon the conversion of the Ni─Cd battery for a screwdriver to lithium cells.
Lithium-ion batteries and their benefits
It is lithium-based batteries that are now constantly heard by many consumers. Partly due to the fact that the lithium compound is used everywhere, in almost any gadget, from a smartphone to a personal laptop. They appeared not so long ago, if we compare the time of their occurrence with nickel-cadmium. only in the 90s of the last century.
It is known that in the beginning, lithium-ion batteries had a high degree of explosion hazard due to technological flaws. At the moment, the overwhelming majority of them are equipped with controllers of charge and heating levels, which ensures their safety and increased periods of productive use.
Why are lithium batteries so remarkable??
Let’s consider their advantages in comparison with their predecessors:
- Higher level of capacity, which increases the life of their continuous use.
- Lack of “memory effect” (at least, vendors and manufacturers claim so).
The high level of capacity ensures the successful use of this particular type of battery in professional technical tools.
For all its advantages, lithium batteries are very sensitive to the slightest voltage fluctuations during charging, as well as to sudden temperature changes. Of course, all chemical current sources are subject to this sensitivity to some extent. But it is not by chance that experts in the field of electronics call this type of batteries “capricious”.
Unlike nickel-cadmium batteries, it makes no sense to purchase lithium batteries with a margin. Over time, they lose their capacity if they are not used for a long time, and their shelf life is no more than two years.
Lithium or nickel-cadmium batteries. which is better?
In fact, the question of which battery is better for a screwdriver is not entirely correct. It all depends on the situation and on the length of time during which the tool will be used.
The lithium battery pack weighs less for the same capacity as cadmium. But this is not the main indicator on the basis of which you should choose a battery for a screwdriver. Of course, the number of charge-discharge cycles for cadmium cells is several times less than that of lithium cells. The standard for Ni-Cd is 500, and for Li it is 1500, which certainly suggests at first that lithium batteries are much better.
When choosing batteries, it is important to consider the fact that the aging of nickel-cadmium batteries depends solely on the cycles they have developed, and not on their actual age. The service life of lithium-ion batteries, in contrast to cadmium, directly depends on the age of the years. After 5 years, they will already be out of order, even if they have not been used. Nickel-cadmium batteries, on the other hand, will last a long time even if they have not been used for a year or more.
For example, when buying a used screwdriver, you should not take it with lithium batteries. There is a high degree of probability that if the tool has not been used for a long time, its battery pack is no longer usable. If a used “Shura” is sold with cadmium batteries, they can save up to 60% of the charge, regardless of whether the worker had a tool or not.
If the screwdriver is not used very often, lithium batteries will “age” rather than serve their intended 1500 cycles. Therefore, for periodic household use, it makes no sense to buy a tool with lithium batteries.
Cadmium can last 8 to 10 years, whether batteries are used or not. It can also lie quietly in the warehouse, retaining its properties, unlike lithium. If you do not plan to use a screwdriver often, the answer to the question of how to choose a battery will be short and truthful: choose cadmium.
By the way, at temperatures down to 20 ° C, cadmium “behaves” better than lithium batteries, which do not like severe frosts. Lithium should be kept at least 60% charged. They need constant recharging when not in use. Otherwise, they start to collapse.
So, if the screwdriver is not used intensively, for occasional household use, choose a tool equipped with a nickel-cadmium battery pack. If you work with a screwdriver every day and professionally, it would certainly be better to opt for lithium, because the batteries will serve their intended 1500 cycles, return and pay off the money invested in them. Don’t overpay for unnecessary cycles if you don’t use the tool frequently and consistently.
Thus, it becomes clear that nickel-cadmium batteries, in fact, are no worse than lithium ones. The main question is only in the field of application of both types of chemical nutrients. When used at the right time and in the right place, both can be equally useful and good. How to replace batteries in a screwdriver, including from Ni-Cd to Li-Ion, read here →
Conversion of a screwdriver to lithium batteries 18650 14 V
When converting screwdrivers of different power and flashlights from Ni-Cd to Li-ion, batteries of the form factor 18650 are more often used. They easily fit into a container or a nest, since instead of two or three relatives, one lithium is installed. Alteration of the screwdriver battery should be carried out taking into account the peculiarities of lithium 18650 batteries.
This type of energy source does not tolerate deep discharge and excessive charge. Hence, it is necessary to use voltage control boards. Since each battery has its own character, their charge is adjusted by a balancer. The point of reworking a screwdriver with a voltage of 14.4 V lies in the creation of a device using lithium batteries to facilitate a hand tool and increase its performance. Lithium 18650 batteries are most suitable for these purposes.
When selecting components, it should be taken into account that the starting current of the screwdriver is high, it is necessary to select the appropriate BMS for the required number of cans and at least 30 A. To convert the charging of the screwdriver to a lithium battery, you must stock up on a good soldering iron, non-acidic flux and thick wires to make jumpers.
- Lithium-ion cans in the amount of 4 pcs.
- 4-cell li-ion battery controller, CF-4S30A-A works well. It has a built-in balancer that controls the charge of each element.
- Hot glue, flux for soldering TAGS, solder.
- Heat-resistant adhesive tape;
- Connecting jumpers or thick insulated wire with a cross section of at least 0.75 squares, cut for bridges.
The procedure for converting a screwdriver for 18650:
- Disassemble the case and remove a bundle of 12 Ni-Cd cells from the container.
- Remove the garland, leaving the connector with the “” and “-” pins. Instead of a temperature sensor, a thermocouple from the controller will be installed.
- Solder the assembly, considering that you cannot use acid, only neutral flux and pure solder. During the connection period, do not warm up the lids. Work pointwise.
- Connect balancing points to the controller according to the diagram. The board has connectors.
- Connect assembly with plus and minus pins.
- Check the functionality of the circuit. If everything works, assembled the battery, place the controller in the socket, secure with sealant.
If the charger is not universal, additional alteration will be required. Screwdrivers for 12 V with a universal charger are assembled in the same way, but a protective connection circuit 3×18650 3.7 V for lithium batteries is used. In the same way, a screwdriver is reworked using a set of 18650 batteries in the amount of 2.
Converting a screwdriver battery to lithium cells
Many screwdriver owners want to convert their batteries to lithium battery cells. Many articles have been written on this topic and in this material I would like to summarize information on this issue. First of all, we will consider the arguments in favor of converting a screwdriver to lithium batteries and against it. And also consider some moments of the process of replacing batteries.
Which battery is better, acidic or lithium?
For a long time, there was no alternative to lead acid batteries for servicing equipment. For boat motors, cars, batteries were created, called starting batteries. Powerful traction batteries are used to constantly deliver energy to motors on electric cars, electric vehicles, stackers and similar equipment.
Is there an alternative to acid and gel models?
Service requirements. The high capacity acid battery charges up to 12 hours. With an incomplete capacity, it can work for 4-6 hours. It is required to install a removable one, which takes time. Only a full charge cycle will save the device from capacity loss. A ventilated room is used for charging, since the evolved hydrogen is explosive.
A lithium-ion device with an active component LiFePO4 has a large capacity, it can be recharged within an hour. It can be energized during downtime, even in 15 minutes. With one battery, you can work around the clock. Namely, lithium-iron-phosphate batteries are actively displacing bulky batteries from storage facilities.
Life time. Acid batteries can withstand up to 1200 recharges, and lithium batteries 3000-5000 times, according to manufacturers. They are maintenance-free and maintenance-free.
The economic factor. Lithium-ion batteries are 3 times more expensive than acid ones. But buying them is economically profitable. When charging and the same amount of work, 30% less energy is spent. The cost of their maintenance is reduced by 65%. No charging room required. The investment pays off within two years.
It is more difficult to decide which starter batteries are better than lithium or acid ones. Here the most important requirement of lithium systems should be taken into account. the exclusion of overcharge and deep discharge. But already leading manufacturers of passenger cars are rebuilding the on-board system, connecting a converter to transfer energy from the generator.
Reasons why it is difficult to convert a car for lithium batteries:
- The generator cannot supply energy directly to the battery. overcharging is possible;
- Power systems. winch, on-board systems must be adapted to the characteristics of the battery;
- The lithium battery for the car floor can be operated up to 20 0. In the future, the capacity is sharply reduced.
On the way are car batteries that do not reduce their capacity at. 40 0. The cost of devices is steadily decreasing.
It is premature to talk about the mass replacement of batteries with lithium ones. Converting a car for a battery can cost more than the energy source itself.
Which lithium batteries are best for a screwdriver
Regardless, we choose a screwdriver or another hand tool, we need to hold it in weight, check how responsive it is in our hand. The Li-ion battery is the choice of professionals. The advantages include high capacity, fast charging and low weight of the tool compared to salt cells. For the amateur who takes the device out of the case every six months, it is better to purchase a screwdriver with an inexpensive nickel-cadmium battery.
Accumulators and batteries
Energy storage information website
Which battery is better, lithium or nickel?
Any battery is a store of energy that has been loaded into it. The principle of operation of the device is based on an electrochemical reaction. The incoming energy starts the electrolysis process. As a result, the ions approach the electrodes, accumulate and thereby create a potential difference, voltage.
Different chemistries use different amounts of energy to create voltage across the terminals. The ability to absorb electric current is called capacitance. By giving the received charge to the tool, the battery ensures its performance.
When comparing lithium and nickel batteries, you can find advantages and disadvantages in both types. This means that you need to choose what is in priority for a particular user. Is a screwdriver better with nickel-cadmium batteries or a lithium battery?
Let’s compare the defining requirements for the tool.
Capacity and its recovery. All nickel batteries have half the capacity of lithium batteries. This means that the operating time is 2 times less. They need to be fully discharged and recharged as well. In this case, the recovery cycle lasts 12-14 hours. Otherwise, the battery will lose capacity due to memory effect due to incomplete charge.
The lithium battery has more capacity and can be charged regardless of the remaining charge. Lithium cells have no “memory” but lose capacity when overcharged or deeply planted. They need special chargers.
Pole voltage. Nickel-cadmium batteries create a voltage of 1.2 V. Different types of lithium cans produce from 3 to 4 V. At the same time, they have a consistently high capacity, most of them are high-current. Screwdrivers use lithium-ion cobalt form factor 18650 and iron phosphate 26650 batteries. Equal voltage tools use less lithium cans, reducing overall product weight.
Temperature factor. Nickel-cadmium batteries work up to 40 0. Almost without losing capacity. Cobalt lithium-ion cells begin to lose their charge already at 10 0, but fail at 10 0 C. It is impossible to charge them in the cold. But iron phosphate elements are inferior in charge density, but they work up to 30 0. At the same time, they are more patient to discharge.
Safety factor. Nickel cadmium batteries pose disposal problems. Cadmium creates a burden on the environment. Lithium ion batteries are prone to fire and explosion when overcharged. The same happens if the ambient temperature is higher than 60 0 С. It is required to use protection boards, special chargers, which increases the cost of products. Iron phosphate lithium-ion batteries do not overheat.
For those who work as a tool from time to time, it is important to know. A lithium battery should be stored at a temperature of 15-20 degrees, pre-charged to 60%. In adverse conditions, the device loses up to 5% of its charge per year. It can be recharged periodically.
The nickel battery is stored discharged. Put on full charge before work.
Knowing the main differences, you can decide which battery is the best, lithium or nickel-cadmium.
We offer you to look at the current topic.
Nickel Cadmium (NiCd)
This type of battery appeared in the middle of the 20th century. Nickel hydrate supplemented with graphite powder acts as a cathode in it. To create the movement of ions from the cathode, an electrolyte is used. potassium hydroxide. The last key element is the anode, which here is made of cadmium oxide hydrate. The second version is metallic cadmium used in powder form.
Estimated service life
The time that the battery will last on a screwdriver depends on the frequency of use and correct use. To some extent, the number of charge cycles is indicative of how long the battery will “live”. Based on this, you might think that lithium ion batteries have the shortest lifespan.
In fact, these batteries do not have a number of disadvantages inherent in other types, due to which, in most cases, these batteries last a longer period.
|Number of charge and discharge cycles||1000||300-500||600|
|The ability to charge quickly||4-8 hours||4-8 hours||30 minutes. 2 hours|
|The cost||cheap||cheap||cost up to 50% of the tool itself|
|Response to tool operation at full power||good performance||good performance||low rates|
|The effect of storing the charge level||there is||there is||no|
|Self-discharge||10% per month||7-10% per month||3-5% per month|
|Working in the cold||can work||can work||poorly tolerate low temperatures|
|Full discharge ratio||tolerate well||tolerate well||must be charged in advance|
Battery selection based on application
So, having thoroughly examined all the key factors, we will discuss with which battery to choose a screwdriver for home and professional activities. This will help you not to overpay and have a reliable tool at hand.
What characteristics are important when choosing a battery for a screwdriver
Considering the advantages and disadvantages of different types of batteries, you can choose the one suitable for specific operating conditions. Now let’s look at two key characteristics that all types of batteries have that affect the choice of a screwdriver.
Number of charge and discharge cycles
All batteries have one drawback. sooner or later they run out of energy and the device must be put on charge. Depending on the type of battery, there is an average statistical limit on the number of charging cycles after which the battery will no longer be able to store current and will have to be replaced.
For screwdrivers with NiCd batteries this figure is 1000 cycles, and the tool often continues to work after reaching this figure. This makes it a leader when compared in this characteristic.
A common type of Li-Ion in screwdrivers is capable of being charged and discharged over 600 times. The advanced technology of the last century NiMh is significantly inferior to the previous ones and the battery will withstand only 300-500 cycles.
Response to tool operation at full power
When you need to drill a hole in a dense material or screw a thick and long self-tapping screw, you have to use the tool at full power. In this case, active consumption of charge begins, and the ability to complete the process qualitatively without a drawdown of revolutions depends on the battery’s reaction to this phenomenon.
In view of this, modern Li-Ion batteries are significantly inferior to their earlier counterparts. The most powerful in this regard are NiCd and NiMh. When maximum energy output is required, then they are chosen.
What does the battery capacity say?
Battery capacity is written in numbers from 1.0 to 7.0 and is measured in amperes times hours (Ah). The value is deciphered as follows: the specified number of amperes can be delivered by the drive within an hour. But since no screwdriver consumes 1-5 A per hour, its usage time stretches from 2 to 8 hours. The higher the capacity, the longer the tool can stay in use.
What does the battery voltage say?
For cordless models, the power and rotation speed of the screwdriver depends on the battery voltage, which must correspond to the parameters of the tool:
- For screwdrivers, the maximum indicator is 36 V. These are the most powerful devices for working with metal and hard wood species.
- 12-18 V. average value suitable for most processes in repair and installation.
- 3-10 V. refer to low-power, and are used only for assembling soft materials or small diameter fasteners.
Installing a battery with a higher capacity on a weaker model will sooner damage the latter. A 12 V battery on an 18 V device will, on the contrary, limit the power of the tool, so the voltage indicator of the drive must exactly match the value on the screwdriver.
Keep in mind that if you take two batteries with the same capacity, a longer tool operation will be provided by the one with a higher voltage.
What batteries can be used for screwdrivers
Power tool manufacturers always indicate in the characteristics of screwdrivers which batteries are recommended for working with them. The battery type is written in several English letters. To know which battery to choose a screwdriver with, you need to understand the decoding of the abbreviation and know the advantages and disadvantages of each type of battery.
This type of battery is the most common, although it is over 100 years old. Nicd batteries have good capacity and low cost.
Nickel-cadmium batteries have the following advantages.
- Durability. With proper operation, the battery can last 8-10 years.
- Ability to work at low temperatures. The battery power is practically not reduced, which allows you to use the tool in the winter outdoors.
- High degree of reliability and unpretentiousness to working conditions.
- The battery can withstand a thousand charge-discharge cycles.
- The battery can be stored for a long time in a discharged state.
Since NiCd batteries are not “afraid” of full discharge, you can work with the tool until it stops completely, that is, until the battery is deeply discharged. Only then can you put it on charge without fear that the battery capacity will decrease.
However, nickel-cadmium batteries are not without their drawbacks. Toxicity of internal battery filling causes disposal problems.
Batteries of this type are quite heavy when compared to other types of batteries. In addition, they have a “memory effect”. This phenomenon occurs in a nickel-cadmium battery when it is prevented from fully discharging. If you turn on such a battery for recharging, then it will “remember” this value and during further work it will discharge exactly to this mark. This will lose a significant portion of the battery’s capacity. The figure below clearly demonstrates how the “memory effect” appears.
Replacing batteries with similar ones
On some units, you can see the mounting screws that need to be removed. But on most battery blocks there are no self-tapping screws, since the body is glued together. To open such a block, you need to carefully insert a screwdriver into the gluing place (shown by an arrow in the photo) and press lightly so that the walls of the case are detached. The same actions need to be done around the entire perimeter.
After opening the block, you will see the batteries in it.
- You need to solder quickly, not allowing the battery to heat up, as it may become unusable.
- For connections, you need to use the “native” plates, desoldering them from the old batteries (they have the desired cross-section and resistance).
- It is important to correctly connect the plus and minus of the battery. The elements must be connected in series: the minus of the previous battery must be connected to the plus of the new one, and the minus of the new battery to the plus terminal of the next battery.
After connecting all the elements, you need to equalize the potentials on all batteries, since they are different. Carry out one charge-discharge cycle: connect the charger to the battery overnight, then let it cool down for a day and measure the output voltage in turn on all cells. If everything went well, then on all batteries the indicator will be the same. within 1.3 V.
Now the battery needs to be discharged by inserting it into a screwdriver and loading the latter to the maximum. The main thing is not to overheat the engine of the tool. Give him a little rest. Bring the battery to full discharge. Repeat this procedure 2 more times (full charge and full discharge).
Li-Ion batteries significantly outperform other types of batteries. The advantages of lithium-ion batteries include the following:
- Almost complete absence of “memory effect”;
- You can recharge the lithium-ion battery at any stage of discharge, without fear of loss of capacity;
- No power loss when battery is low;
- The effective service life is 5-8 years;
- Low self-discharge;
- It takes little time to charge;
- There are no toxic elements;
- High power with small dimensions.
Cons of lithium-ion batteries:
- Shock sensitivity (may explode on strong impacts);
- The battery does not tolerate full discharge and overcharge. this causes the battery to fail;
- Discharges quickly at low temperatures;
- High price;
- Service life is lower than that of nickel-cadmium batteries.
It is difficult to say unequivocally which battery is better. Mainly, you must decide for what purpose you are going to purchase a screwdriver. If for home use, which implies infrequent switching on with long interruptions in work, then you need to choose a tool with a nickel-cadmium battery.
Lithium-ion batteries are the professional choice. They are designed for continuous, long-term and continuous operation. The recharge time of the battery is also important for a professional tool. But it is worth remembering one rule: a lithium battery cannot be brought to full discharge.
Nickel-metal hydride batteries
Nimh batteries were designed to overcome the disadvantages of nickel cadmium batteries. The positive characteristics of nickel-melall hydride batteries are as follows:
- Have smaller dimensions and weight;
- Low toxicity;
- The “memory effect” is poorly expressed;
- They have high capacitive characteristics;
- Resistant to mechanical damage;
- The number of charge-discharge cycles has increased (up to 1500).
However, NiMH batteries have their drawbacks:
- It is forbidden to use them at negative ambient temperatures;
- The battery tends to discharge quickly;
- Shorter battery life when compared to nickel-cadmium batteries;
- High price;
- It takes a long time to charge;
- The battery does not “tolerate” deep discharge.
Thus, although NiMH batteries were designed to compete with nickel-cadmium batteries, they are significantly inferior in performance to the latter.
Varieties of batteries for a screwdriver
There are 3 types of rechargeable batteries on the power tool market:
- (NiCd) nickel-cadmium;
- (NiMH) nickel metal hydride;
- (Li-Ion) lithium-ion.
How can you replace the “native” battery in a screwdriver
If the batteries in your screwdriver have worn out, they can be easily replaced. There is such a thing as battery interchangeability. For example, under the PowerPlant brand, batteries are produced that are compatible with most popular brands of power tools. They cost much less than “native” batteries and are quite efficient.
But if this option does not suit you, then the batteries themselves in the unit can be replaced with new ones. To do this, you will have to disassemble the battery pack and remove the elements that make up it.
Replacement with lithium batteries
Replacing NiCd cells with Li-Ion is also not difficult. It is known from the school course that if the batteries are connected in series, then their voltage ratings will be summed up. For example, your screwdriver runs on a battery with a voltage of 14.4 V, which means that it can be replaced with four 3.3 V finger batteries. This voltage will be enough, because the lithium batteries do not “sag too much” when starting the device.
It is recommended to buy batteries from reputable manufacturers, for example, Sistem A123. The LiFePO4 battery of this company has a capacity of 2400 mAh, sufficient for the normal functioning of the screwdriver. If you buy batteries via the Internet, then they will cost you less. around 900 rubles for 3 pieces.
You will also need to purchase soldering acid instead of alcohol flux. In this case, overheating of the batteries will be minimized. The soldering iron must have a power within 65W.
You can learn more about how batteries are replaced with lithium batteries by looking at this.
Which battery for a screwdriver is better to choose
A cordless screwdriver is a fairly convenient and popular tool. Independence from the power supply makes this device mobile and allows you to work in hard-to-reach places. But despite all the advantages, the rechargeable battery (AKB) is the weak link in a screwdriver. Therefore, when choosing a power tool, you first need to understand what types of batteries exist, what is their difference, the pros and cons of different types of batteries.
DIY screwdriver battery charger
If your screwdriver charger is out of order, or you redesigned the tool battery by replacing NiCd batteries with Li-Ion cells, then you will need to get a new charger. Below is a diagram of a charger capable of providing a charging current suitable for any type of battery.
This charger is a current generator based on the VT2 transistor. The latter is powered by a rectifier bridge. The bridge, in turn, is connected to a step-down transformer with the required output voltage. This transformer must have good power so that it can work for a long time without overheating, providing the required current. Otherwise, the transformer may burn out. The voltage supplied by the transformer must not exceed 27 V.
The charge current is regulated by the resistor R1 (the battery for the screwdriver must be connected). It must remain constant throughout the entire charging process. Resistor R3 is designed to limit the maximum current. The VD6 LED will stay on as long as the charge is in progress. When the charging process comes to an end, the light of the LED will begin to decrease, and it will go out.
All elements of the electronic circuit are installed on a PCB made of PCB covered with a layer of copper foil. The diodes indicated in the diagram can be replaced with diodes taken from old radio equipment, KD202 or D242. Parts on the board must be placed in such a way that there are no intersections. High density of placement of parts is not required. If you leave 3-5 mm between them, then it will be easier to solder. Be sure to install the transistor on a radiator with an area of at least 20-50 cm 2.
Based on the dimensions of the board, you will need to make a case (it can be made of plastic) using a glue gun. The table below contains the entire list of required radio components.
If you build the charger following this diagram, you will get a reliable, simple and inexpensive charging for your screwdriver.